Some of today's current weapons systems, like the Paveway III, use dual axis spinning mass gyros to establish an inertial coordinate frame after weapon release from an aircraft. The Humphrey gyroscope found in the Paveway III has a 100 ms start time. A rapid start time allows for quick establishment of a local vertical after the weapon is released and begins to roll. Keeping track of this rolling motion can be important to determining the orientation and attitude of the weapon.